Table 1 Vaccination, screening, cost parameters and transition probabilities
From: Cost-effectiveness of different human papillomavirus vaccines in Singapore
| Parameters | Base case | Ranges | Source |
|---|---|---|---|
| Vaccination | |||
| Cohort size | 25,000 | [20] | |
| Vaccine coverage | 100% | Assumption | |
| Age at vaccination | 12 | ||
| Vaccine efficacy* - bivalent vaccine | 87.2% | 70%-95% | [21, 22] |
| Vaccine efficacy* - quadrivalent vaccine | 78.8% | 70%-95% | [23] |
| Duration of efficacy | Lifetime | 5 years to lifetime | Assumption |
| Vaccine waning + booster | None | 5, 10, 20 years | Assumption |
| Screening | |||
| Screening age range | 25-65 | [4] | |
| Screening interval | every 3 years | [4] | |
| Percentage screened per year | 17% | 10-20 | Estimated |
| Cytology sensitivity to detect CIN1 | 0.58 | none | [18, 19] |
| Cytology sensitivity to detect CIN2/3 | 0.61 | none | [18, 19] |
| Compliance to CIN1 treatment | 75% | 50%-100% | Assumption |
| Compliance to CIN2/3 treatment | 75% | 50%-100% | Assumption |
| Cancer detection rate | Low | High | |
| Probability Of symptons CC1 | 0.075 | 0.185 | |
| Probability Of symptons CC2 | 0.113 | 0.3 | |
| Probability Of symptons CC3 | 0.3 | 0.75 | [24, 25] |
| Probability Of symptons CC4 | 0.45 | 0.8 | |
| Cost, SGD$ (2008) | (-20%/+50%) except vaccine cost (200-400) | ||
| Vaccine cost per vaccinated woman, bivalent vaccine # | 400 | ||
| Vaccine cost per vaccinated woman, quadrivalent vaccine# | 400 | Assumption | |
| Cytology test^ | 40 | ||
| Colposcopy and Biopsy^ | 207 | ||
| CIN 1 treatment | 1,105 | ||
| CIN 2/3 treatment | 1,480 | ||
| Stage 1 Cancer treatment cost | 9,388 | Singapore public sector hospitals | |
| Stage 2 Cancer treatment cost | 9,765 | ||
| Stage 3 Cancer treatment cost | 9,765 | ||
| Stage 4 Cancer treatment cost | 11,047 | ||
| Genital warts | 750 | ||
| Discounting | |||
| Costs, Outcomes | 3%, 3% | (0%-5%) | Assumption |
| Transition Probabilities | |||
| Well to HPV | 0.05 | 0-0.2 | |
| HPV to clearance | 0.4 | 0.29-0.55 | |
| HPV to CIN1 | 0.05 | 0.014-0.14 | [18, 19, 26] |
| CIN1 clearance | 0.4 | 0.24-0.5 | |
| CIN1 to CIN2/3 | 0.09 | 0.02-0.32 | |
| CIN2/3 clearance | 0.25 | 0.01-0.45 | |
| CIN2/3 to persistent CIN2/3 | 0.11 | 0.03-0.20 | |
| Persistent CIN2/3 to Cancer stage 1 | 0.05 | 0.001-0.15 | |
| Cancer stage 1 to Cancer stage 2 | 0.22 | 0.11-0.4 | |
| Cancer 1 to cancer cured | 0.84 | 0.63-0.98 | |
| Cancer stage 1 to Cancer stage 3 | 0.24 | 0.12-0.5 | |
| Cancer 2 to cancer cured | 0.66 | 0.49-0.83 | |
| Cancer stage 3 to Cancer stage 4 | 0.24 | 0.12-0.8 | |
| Cancer 3 to cancer cured | 0.38 | 0.28-0.48 | [21, 22, 24–26] |
| Cancer 4 to cancer cured | 0.11 | 0.08-0.14 | |
| Detected CIN1 to well | 0.9 | 0.8-1 | |
| Detected CIN1 to Detected CIN2/3 | 0.09 | 0.02-0.32 | |
| Detected CIN2/3 to Well | 0.9 | 0.8-1 | |
| Detected CIN2/3 to Detected PCIN2/3 | 0.11 | 0.03-0.20 | |
| Detected PCIN2/3 to Cancer 1 | 0.05 | 0.001-0.15 | |
| Mortality of cervical cancer | 0.11 | ||
| Cervical Warts | |||
| Effectiveness of vaccination against warts | 0.90 | [27, 28] | |
| Cost of treatment | 750 | ||
| Well to low risk HPV | 0.050 | ||
| Low risk HPV to well | 0.500 | ||
| Low risk HPV to CIN1 low risk | 0.036 | ||
| Low risk HPV to warts | 0.027 | ||
| Warts to well | 0.875 | ||
| CIN1 low risk to well | 0.500 | ||
| CIN1 low risk to detected CIN 1 low risk | 0.099 | ||
| Detected CIN 1 low risk to well | 0.950 | ||
| QALYs | |||
| Disease free | 1 | ||
| Genital warts | 0.96 | 0.91-0.99 | [10, 25, 29] |
| Detected CIN | 0.89 | 0.84-0.94 | |
| Cancer detected | |||
| Stage I | 0.65 | 0.49-0.81 | |
| Stage II | 0.56 | 0.42-0.70 | |
| Stage III | 0.56 | 0.42-0.70 | |
| Stage IV | 0.48 | 0.36-0.60 | |
| Cancer cured | 0.94 |